Ryoichi Fujiwara

Post-doctoral Researcher

Contact Info:
University of California, San Diego
9500 Gillman Drive
La Jolla, CA 92093-0722

Email:

Phone Number:
858-822-1351

Bio/Research Summary:

I completed my graduate work under the guidance of Dr. Yokoi in the Division of Pharmaceutical Sciences at Kanazawa University. While a graduate student, I had been working in the area of Drug Metabolism and advancing our understanding of the substrate specificity and protein-protein interactions of a phase II drug-metabolizing enzyme, human UDP-glucuronosyltransferase (UGT). I joined Dr. Tukey’s laboratory with a near global knowledge in this area. I have been investigating the impact of human glucuronidation on bilirubin metabolism using recently developed humanized model mice.

Publications:

1. Fujiwara R, Nakajima M, Yamanaka H, Nakamura A, Katoh M, Ikushiro S, and Yokoi T. Effects of coexpression of UGT1A9 on enzymatic activities of human UGT1A isoforms. Drug Metab. Dispos. 35: 747-757, 2007.

2. Nakajima M, Yamanaka H, Fujiwara R, Katoh M, and Yokoi T. Stereoselective glucuronidation of 5-(4’-hydroxyphenyl)-5-phenylhydantoin by human UDP-glucuronosyltransferase (UGT) 1A1, UGT1A9, and UGT2B15: effects of UGT-UGT interactions. Drug Metab. Dispos. 35: 1679-1686, 2007.

3. Fujiwara R, Nakajima M, Yamanaka H, Katoh M, and Yokoi T. Interactions between human UGT1A1, UGT1A4, and UGT1A6 affect their enzymatic activities. Drug Metab. Dispos. 35: 1781-1787, 2007.

4. Fujiwara R, Nakajima M, Yamanaka H, Katoh M, and Yokoi T. Product inhibition of UDP-glucuronosyltransferase (UGT) enzymes by UDP obfuscates the inhibitory effects of UGT substrates. Drug Metab. Dispos. 36: 361-367, 2008.

5. Nakamura A, Nakajima M, Yamanaka H, Fujiwara R, and Yokoi T. Expression of UGT1A and UGT2B mRNA in human normal tissues and various cell lines. Drug Metab. Dispos. 36: 1461-1464, 2008.

6. Fujiwara R, Nakajima M, Yamanaka H, and Yokoi T. Key amino acid residues responsible for the differences in substrate specificity of human UDP-glucuronosyltransferase (UGT) 1A9 and UGT1A8. Drug Metab. Dispos. 37: 41-46, 2009.

7. Fujiwara R, Nakajima M, Yamamoto T, Nagao H, and Yokoi T. In silico and in vitro approaches to elucidate the thermal stability of human UDP-glucuronosyltransferase (UGT) 1A9. Drug Metab. Pharmacokinet. 24: 235-244, 2009.

8. Izukawa T, Nakajima M, Fujiwara R, Yamanaka H, Fukami T, Takamiya M, Aoki Y, Ikushiro S, Sakaki T, and Yokoi T. Quantitative analysis of UDP-glucuronosyltransferase (UGT) 1A and UGT2B expression levels in human livers. Drug Metab. Dispos. 37: 1759-1768, 2009.

9. Fujiwara R, Nakajima M, Oda S, Yamanaka H, Ikushiro S, Sakaki T, and Yokoi T. Interactions between human UDP-glucuronosyltransferase (UGT) 2B7 and UGT1A enzymes. J Pharm Sci. 99: 442-452, 2010.

10. Nakajima M, Koga T, Sakai H, Yamanaka H, Fujiwara R, and Yokoi T. N-Glycosylation plays a role in protein folding of human UGT1A1. Biochem Pharmacol. 79: 1165-1172, 2010.

11. Fujiwara R, Nguyen N, Chen S, Tukey RH. 2010. Developmental hyperbilirubinemia and CNS toxicity in mice humanized with the UDP-Glucuronosyltransferase 1 (UGT1) locus. Proc Natl Acad Sci USA 107: 5024-5029, 2010.

12. Fujiwara R, Chen S, Karin M, Tukey RH. Reduced Expression of UGT1A1 in Intestines of Humanized UGT1 Mice, via Inactivation of NF-ĸB, Leads to Hyperbilirubinemia. Gastroenterology. 2011. In Press